The process that is the object of this application is a process for alkyations or transalkylating aromatic compounds for the purpose of producing alkylaromatic compounds. The aromatic monoalkyls find a use in the composition of gasolines or lyes, aromatic dialkyls and trialkyls in the field of lubricants.
The process according to the invention thus makes possible the production of mono-, di- and trialkyl aromatic compounds. This process thus relates to the alkylation of aromatic compounds (benzene, toluene, cumene) by alkylating agents (olefins, alcohol, halides) for producing aromatic monoalkyls whose grafted aliphatic chain comprises a carbon number that is selected from 2 to 20 carbon atoms.
This process can also produce dialkylbenzenes, i.e., aromatic compounds where the benzene core comprises two paraffin chains whose carbon atom number can be identical or different. Each of these aliphatic chains can contain 2 to 20 carbon atoms. In the case where it would be desired to produce aromatic trialkyls, there are three aliphatic chains of which two, for example, have identical lengths.
The alkylation of aromatic compounds has been known for many years.
U.S. Pat. No. 2,939,890 (Universal Oil Products Company), dating from 1960, thus claims a process or synthesis or cumene by using BF3 as a catalyst.
U.S. Pat. No. 3,173,965 (Esso Research), dating from 1965, which claims as suitable catalysts for the alkylation of benzene acids of type AlCl3, AlBr3, FeCl3, SnCl4, BF3, H2SO4, P2O5 and H3PO4is also known.
In the same connection, U.S. Pat. No. 4,148,834 (1979) and U.S. Pat. No. 4,551,573 (1985) claim the use for the first of HF during the first stage and AlCl3 or AlBr2 in the second stare. The second patent claims, more particularly, a mixture of aluminum halides and elementary iodine.
U.S. Pat. No. 3,251,897 claims the use of X and Y zeolites that are exchanged with rare earths for the production of monoalkyl benzene (ethylbenzene, cumene) and diethylbenzene.
U.S. Pat. No. 3,631,120 (1971) claims the use of zeolites, mainly Y zeolite, having a silica to alumina ratio of 4 to 4.9 for the production of cumene.
U.S. Pat. No. 5,107,048 (1992) claims the use of an amorphous catalyst of the silica type promoted as Lewis acid using BF3.
The process, claimed by the applicant, relates to the production of monoalkyl benzene and/or dialkyl benzene and/or trialkyl benzene and has as original features:
a production flowsheet that is flexible and that makes it possible to adapt it to the needs of the market or to the possibilities of supply,
the catalysts that are used are neither dangerous nor toxic as are the aluminum halides or HF,
their specificity is such that it makes it possible to obtain products of high purity,
the catalysts that are used in this invention can be regenerated by simple combustion with air or under oxygen or referenced by a treatment under hydrogen.
The invention is therefore essentially characterized by a flexible process that normally comprises in series two combined stages that are suitable for producing, jointly or otherwise, mono-, di- and trialkyl aromatic compounds.
Process in which based on the desired products, either the two stages or the first or the second of these two stages, whereby each of the stages can be switched off or restarted at any time, can be used based on the requirements of the clientele to be supplied in mono-, di- or trialkyl aromatic compound that are obtained by alkylation or by transalkylation of an aromatic hydrocarbon by an olefinic compound.
The three types of products that can be produced by the process of which the applicant claims the property correspond to the following generic chemical formulas: 
These alkyl chains each have 2 to 20 carbon atoms. These chains can have equal dimensions or different lengths.
The products that are obtained consist of three isomers: ortho, meta and para. 
Here, aliphatic chains R1 and R2 can have identical or different lengths and comprise 2 to 20 carbon atoms.
In the process, four different types of production can be considered separately when only a single specific product is desired:
Case 1: Production of dialkyl benzene for which the aliphatic chains are of different lengths,
Case 2: Production of dialkyl benzene for which the aliphatic chains are of identical length,
Case 3: Production of monoalkyl benzene,
Case 4: Production of trialkyl benzene. 